Exemplary embodiments of the present invention relate to a shaping apparatus for manufacturing a profiled component and a method for producing a profiled component.
Profiled components are used for example in vehicle structures, e.g. in load-dissipating structures. Profiled components are used, for example, as curved structural components in the hull construction of an aircraft, for example an airplane, for example as a stringer or a rib. The profiled components are produced, for example, from a flat semi-finished product by a corresponding shaping process. In line with efforts towards achieving reduced fuel consumption and the concomitant strive towards minimizing weight, profiled components are made, for example, from a fiber-reinforced composite material. To this end, for example fibrous structures, together with a matrix material, are laid onto a template having the corresponding profile and are subsequently cured into the finished profiled component using compression and heating steps. In order to apply the required pressure vacuum films are used that extend over the laid-out semi-finished product in the form of the fiber layers, which may, for example, be impregnated with a matrix material, so that as a result of the application of a vacuum in the region between a base plate and the vacuum film, a corresponding pressure can be applied onto the semi-finished product. In the course of this, the semi-finished product is made to lie against the underlying template. Apart from laying out individual fiber layers into the given template, also mats prepared as so-called prepregs are used, which are made up from a plurality of layers of fiber mats and a binder or matrix material applied thereto, so that the mat laid out on the template will initially only approximately adapt to the template and will not lie exactly against it. The exact laying-on process, which to a certain extent is a reshaping, is then carried out using a vacuum film. Therefore, also the term diaphragm shaping is used for this method. When manufacturing profiled components, it is also known to assemble individual profiled segments into a profiled component. For example, flat profiled regions may be combined with a so-called omega profile in order to form a type of hollow profile. The connection is then carried out by bonding, e.g. under the effect of heat and pressure. European patent document EP 2 253 460 A2 discloses a connection system for composite and metal components, wherein the regions to be connected are pressed against each other by pressure chambers, the pressure chambers are equipped with a stretchable and elastically deformable membrane, so that in the pressure chamber, a pressure may be applied via a fluid so as to act uniformly onto the surfaces to be joined. The surfaces to be joined are preformed, so that the elastic membrane ensures a uniform pressing on. The pressure chambers are accommodated in housing structures having an elastically deformable membrane only in the region of the joint to be pressed together. However, in order to join a plurality of profile regions, the method known from European patent document EP 2 253 460 A2 requires the prefabrication of the individual already finish-profiled profile elements. However, it has been shown that the handling of fiber mats, for example prepregs, and the required placing into a template structure is complex and therefore cost-intensive. Moreover, the pressing on of a semi-finished product by way of diaphragm shaping is insufficient in the case of tight internal radii, because in these regions, only insufficient pressure can be applied by means of the vacuum film.
Exemplary embodiments of the present invention are directed to providing a simplified way of manufacturing a profiled component having an improved component quality.
According to the invention, a shaping apparatus for manufacturing a profiled component is provided, wherein the shaping apparatus includes a lay-on unit, a press-on unit and a pressure application unit. The lay-on unit includes a support surface for laying on a semi-finished product to be shaped. The press-on unit is provided for pressing a semi-finished product to be shaped against the support surface. The pressure application unit has, at least on the side that faces the semi-finished product, a bendable shell for lying against the semi-finished product in an unshaped first state and for lying on in a shaped second state, as well as a pressure-transmitting and deformable filling. The pressure application unit can be disposed between the press-on unit and a semi-finished product to be shaped. The press-on unit has a bendable surface that lies on the pressure application unit, which bendable surface transmits the force for the shaping onto the pressure application unit.
The term “profiled” relates, for example, to an elongated component that is formed with a profiled cross-section. The term “profiled” also relates to an elongated component that is curved in a longitudinal direction. Moreover, “profiled” also relates to a component that is formed with a cross-sectional profile in the transverse direction and that is moreover formed in a curved manner in the longitudinal direction.
The term “shaping” comprises, for example, the laying of an initially flat semi-finished product, for example of a more or less flat semi-finished product, on a support surface that is provided as a shape-imparting structure.
The term “bendable shell” relates to an enveloping material that may be bent or deformed like a film and which can therefore be adapted to various profiles, however which is not stretchable or elastic in its longitudinal direction, i.e. in the direction of the enveloping surface. The bendable shell must in any case be capable of maintaining the enclosed volume, i.e. it must be possible for an applied pressure to be also transmitted.
The term “bendable surface” relates to a surface for lying on the pressure application unit, which at least at the level of the surface is soft enough to conform to the different contours of the pressure application unit. The bendable surface may be formed as a tension-resistant membrane or film. The bendable surface may also be formed as an elastic membrane or film. The bendable surface may also be a laminate having a conformable shape, i.e. surface shape, or a bendable plate element.
According to one exemplary embodiment the semi-finished product to be shaped is a fiber-reinforced composite material.
For example, the fiber-reinforced composite material includes a composite laminate. The term “composite laminate” refers to a material that may include, in addition to a fiber-reinforced composite material, further material layers and/or material inserts, such as e.g. a metal fabric, a metal foil and the like. The shaped semi-finished product will then be used, upon passing through further operating steps, as a stringer or a rib on an aircraft. The further operating steps may include, for example, curing the profiled semi-finished product shaped.
The support surface includes, for example, concave or recessed regions, e.g. regions with interior edges and/or interior corners.
The support surface forms a template counter-piece for shaping the semi-finished product to be shaped.
The semi-finished product to be shaped is provided e.g. as an inherently stable plate, i.e. as a self-supporting plate, which after having been laid onto the support surface, will not or only to a very minor extent adapt to the structure of the support surface underneath it.
According to a further embodiment, the pressure application unit is provided all around with a bendable shell.
For example, the pressure application unit forms a bladder filled with a fluid.
According to a further embodiment, the bendable surface of the press-on unit lies on the one side of the pressure application unit, and on the other side, a pressure can be applied thereto via a fluid for transmitting the force for the shaping. For the pressure application it is provided that:
i) the bendable surface forms a volume onto which pressure can be applied; or
ii) the bendable surface is a vacuum membrane, with a vacuum unit being provided for generating a negative pressure in a region between the vacuum membrane and the support surface in such a way that ambient air pressure acting from the outside on the vacuum membrane effects a shaping by laying the semi-finished product onto the support surface.
The volume onto which pressure can be applied is filled for example with a fluid, e.g. with pressurized air or another pressure-transmitting medium such as water or oil, or a pressure is applied onto the fluid.
The vacuum membrane is, for example, a vacuum film. The vacuum unit is for example a vacuum pump that is in communication with the region between the vacuum membrane and the support surface.
In one example, the pressure application unit is integrated into the vacuum membrane.
For example, the vacuum membrane is designed in multiple layers and includes, at least partly, a cavity that is provided with the pressure-transmitting and deformable filling.
According to a further embodiment, the bendable surface of the press-on unit is held by holding points in such a way that the bendable surface forms a convex contour both in the unshaped first state and in the shaped second state. Tension stress can be applied onto the bendable surface for transmitting the force for the shaping.
In a further example, the pressure application unit is integrated into the bendable surface, e.g. integrated in a film that can be subjected to tensile stress.
According to a further embodiment, the pressure application unit has as a filling at least one member of the group of gaseous fluids, liquids, gels and loose bulk solids.
For example, the pressure-transmitting and deformable filling includes a fluid medium. According to one example, the liquid is stable under pressure. The filling may e.g. be a highly viscous filling.
According to a further embodiment, the filling of the pressure application unit may have a dynamic viscosity of at least 100 Pa·s.
According to a further embodiment example, the pressure application unit has such a volume that, when the pressure application unit lies on the support surface, all of the recesses of the support surface are filled by the pressure application unit, so that the vacuum membrane forms a convex enveloping surface.
The recesses form for example concave shape regions.
The forming of a convex enveloping surface in a maximally compressed state offers, for example, the advantage that while vacuum is applied, the vacuum membrane is at no point stretched again in relation to the underlying pressure application unit, or is as it were relaxed, as would be the case if the vacuum membrane initially formed a convex enveloping surface and would, during further shaping, form an enveloping surface with concave regions.
According to one embodiment example, the pressure application unit includes a replaceable pressure application element.
According to a further embodiment example, the pressure application unit includes a plurality of pressure application elements, which may for example, also be designed to be replaceable.
For example, several pressure application elements are provided next to each other, one after the other and/or on top of each other (in the direction of the applied pressure).
It is also possible to combine a number of pressure application elements to form one pressure application unit.
For example, a pressure application unit, or a pressure application element, may also be designed with a plurality of chambers, e.g. by means of inserted partitions, which at least reduce, or even completely stop, the flow or movement of the filling from one chamber to the next.
According to a further embodiment the pressure application unit can be tempered and that the pressure application unit can be used to supply thermal energy to a semi-finished product to be shaped, and/or can also be discharged therefrom.
According to a further embodiment, the support surface is replaceable and various surface profiles may be inserted.
According to the invention, a method for producing a profiled component is provided, which comprises the following steps:
a) arranging a semi-finished product to be shaped on a support surface of a lay-on unit;
b) arranging a pressure application unit on the semi-finished product that includes, at least on the side that faces the semi-finished product, a bendable shell to lie against the semi-finished product in an unshaped first state and to lie on in a shaped second state, and a pressure-transmitting and deformable filling;c) arranging a press-on unit on the pressure application unit, wherein the press-on unit has a bendable surface that lies on the pressure application unit, where the bendable surface is used to transmit the force for the shaping onto the pressure application unit;d) pressing the semi-finished product to be shaped against the support surface by means of the press-on unit via the pressure application unit and shaping it at the same time.
According to an exemplary embodiment of the method, the bendable surface of the press-on unit lies on the one side on the pressure application unit and on the other side, a pressure is applied thereto via a fluid for transmitting the force for the shaping. Moreover, it is provided for the pressure application that:
i) the bendable surface forms a volume onto which pressure may be applied; or
ii) the bendable surface is a vacuum membrane, and wherein in step (d) a negative pressure is generated in a region between the vacuum membrane at the support surface by means of a vacuum unit, so that air pressure acting from the outside on the vacuum membrane acts via the pressure application unit and effects shaping by laying the semi-finished product against the support surface.
According to an exemplary embodiment, the bendable surface of the press-on unit is held by holding points in such a way that the bendable surface forms a convex contour both in the unshaped first state and in the shaped second state, and a tensile stress is applied onto the bendable surface for transmitting the force for the shaping.
For example, the bendable surface, which is formed e.g. as a film, is held by a first lateral edge on a base surface, on which the support surface of the lay-on unit is provided. The film is now laid over the semi-finished product to be shaped and a tensile stress is applied onto a second lateral edge, so that the film exerts a compressive force onto the pressure application unit, which ultimately acts on the semi-finished product.
According to a further embodiment example, in order to soften the semi-finished product, the latter is tempered by the pressure application unit prior to step (d).
According to the present invention, also the use of the apparatus described above is provided for producing a profiled component.
According to the invention, a flexible element is used for shaping a semi-finished product, which due to its capability of lying intimately against it, effects an improved shaping of the semi-finished product by way of an improved pressing on of the semi-finished product especially on internal radii. The pressure-transmitting and deformable filling may, for example, also be used as a heat transfer medium, in order to heat for example a semi-finished product provided as a laminate and also to soften it in order to support the shaping operation. By using a medium with a higher viscosity, such as e.g. a gel, the pressure-transmitting intermediate body may also be used in regions where, for example, due to gravity, an unfavorable flowing off or migrating of the filling might occur. For example, compared to a rigid compression die, the deformable element provided according to the invention may be used to achieve a good degree of shaping during the shaping of the semi-finished product and also in the case of slightly deviating shapes, in particular in the case of varying internal radii or internal edges or internal corners. Unlike rigid shaping dies, the shaping apparatus can be used, as a result of the flexibility of the pressure element, without setting up time for various sub-templates. The flexible intermediate element effects an improved pressing against the shaped structure underneath it.
It should be noted the features of the embodiment examples and of the apparatus also apply to the embodiments of the method as well as to the use of the apparatus, and vice versa. Moreover, also those features may be freely combined where this has not been explicitly mentioned.